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(No Model.) 4 Sheets-Sheet 1.

J; P. FREEMAN.

TELEPHONE TRANSMITTER.

No. 318,424. Patented May 19, 1885.

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J. P. FREEMAN. TELEPHONE TRANSMITTER.

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(No Model. I 4 Sheets-Sheet 3. J. P. FREEMAN.

' TELEPHONE TRANSMITTER.

No. 318 424. Patented May 19, 1885.

(No Model.) 4 Sheets-Sheet 4. J. P. FREEMAN.

TELEPHONE TRANSMITTER. No. 318,424. Patented May 19, 1885..

N PETERS mmmno u h w h 1 m0 C Jarret Srarns Faranr rrrcn.

JAMES P. FREEMAN, OF CHICAGO, ILLINOIS, ASSIGNOR OF NINE-T\VEN- TIETHS TO E. M. MARBLE, OF WVASHINGTON, DISTRICT OF COLUMBIA.

TELEPHONE-TRANSNI ITTER.

SPECIFICATION formin part of Letters Patent No. 318,424, dated May 19, 1885.

Application filed April 21, 1885.

ffo all whom it may concern.-

Be it known that 1', JAMEs P. FREEMAN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Telephone-Transmitters, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to telephonic transmitters of the class known as battery-trans mitters; and its object is to utilize for telephonic transmission an intermittent electrical current instead of the so-called continuous undnlatory current employed in variable contact closed circuit transmitting instruments, as heretofore constructed.

My invention in part consists in breaking and closing the primary circuits of an induc tion-coil rapidly in response to the vibrations of a diaphragm actuated by sound-vibrations of the air, and thereby causing said circuits to be traversed intermittingly by strong electric impulses which have the effect to induce in the secondary circuit and the line-wire connected thereto impulses of alternating direction, having quantity and tension so great that they will travel over very long stretches of linewire and actuate receiving-instruments connected therein with greater force than has heretofore been known in the art of telephony, reproducing articulate speech clearly, loudly, and distinctly; and in part in a novel combination in a transmitting-instrument of circuit closing and breaking devices with a diaphragm, battery-circuits, and an induct-ioncoil having two primaries and one secondary coil, which will be hereinafter more fully described, and pointed out in the claims.

In the accompanying drawings, forming a part of this specification, and in which similar letters refer to like parts, Figure 1 is a perspective view of the door of a transmitter box or casing having mounted thereon the dia phragm and circuit closing and breaking devices. Fig. 2 is a view in elevation of the transmitter-box with its door open to show the interior parts. Fig. 3 is a section of the door and diaphragm in the plane of the vertical diameter of the latter, the circuit closing (No model.)

and breaking devices and induction-coil being shown in full lines. Fig. 4 is a detached end elevation of the working lever and elec trodes. Fig. 5 is a section of the door and diaphragm and view in elevation of an inductus, and A is its door having the diaphragm 6 D mounted behind an orifice, 66, therein in the usual manner. From the center of the rear surface of the diaphragm projects a pin, 0, and behind this pin is an approximately equal armed rocking lever, F, pivoted to an arm,f,

which stands behind the diaphragm, and is supported by a post, f, projecting rearwardly from the door A. This rocking lever F has in sorted through openings in its ends insulating or non-conducting plugs and through these plugs are secured metallic pins [L h, the forward ends of which are arranged to make contact with the tips of metallic spring-fingers I l, which project from the door A and stand at a little distance from the rear face of the dia- 30 phragm. The rear ends of the pins h h are arranged to make contact with the respective carbon electrodes K K, carried by metallic strip-springs 7t 7t, projecting from metallic swin -arms Z Z which )rocct rearwardl 8: l a v e from the door A. Each of these spring-arms has behind it a post, Z through which passes an adjusting-screw, P, the tip of which bears against said arm. By means of these screws the arms may be adjusted to cause the springs 0 to hold the carbon electrodes in proper relation to the contact-pins. These spring-fur gers, spring-arms, electrodes, rocking lever, and'contactpins constitute, in connection with the diaphragm, the circuit closing and break- 5 ing devices, and with them I use an induction-coil of peculiar construction, in that it has two primary coils, one of which is preferably arranged within the secondary coil in the usual manner, while the other is wound 10o Fig. 7 is 60 outside of the secondary coil. I have illustrated such an induction-coilin Fig. 7, though I wish it to be understood that I do not con fine myself to this form, the essential requirement being only that there shall be two primary coils which act alternately for inducing currents in the secondary.

In the figure, M is the secondary coil, m the inner primary, and m the outer primary coil. Now, in connecting this coil for use I connect the outer terminal of the outer primary coil with the spring-arm Z, and the inner terminal with one pole of a battery, X, which has its other pole connected with the spri'ngfinger I. The outer terminal of the inner primary coil is connected with the spring arm Z, and the inner terminal of this inner primary coil is connected with one pole of a battery, X, the other pole of which is connected with the spring-finger I. It will now be seen that if the spring-finger I is in contact with the forward end of the contact-pin h, and the rear end of said pin is in contact with the carbon electrode K, the circuit of battery. X will be closed through the spring-finger I, contactpin h, carbon electrode K, strip-spring 7c, arm Z, and the conductors, including the outer primary circuit, which connect said arm and spring-finger I with the opposite poles of the battery. If, instead of the pin h being in contact with its adjacent spring-finger and carbon electrode, the pin h should be in contact .with the spring-finger I and the carbon electrode K, then the circuit of battery X would be closed through the inner primary circuit, as will be readily understood.

The actual mechanical arrangement of'the conductors and other parts is illustrated in Fig. 2, in which the induction-coil is indicated by M, and 'w w are the terminals of its secondary coil leading to binding-posts o o. The outer terminal of the outer primary is connectcd by a wire, w, with one side of the lower door-hinge, 9', from the other side of which a wire, 10*, leads to an arm, Z. The inner terminal of the outer primary is connected by a wire, 10 with binding-post 2, which is to be connected with one pole of the battery X,

the other pole of which is to be connected with binding-post z, which is connected by a wire, w, with one side of hingej, the other side of which is connected by a wire, 105, with springfingcr I. The outer terminal of the inner primary is connected by a wire, 10, with one side of binge j, the other side of which is connected by wire 20 with arm Z, while the inner terminal of this inner primary is connected by a Wire, 20 to binding-post z". This post is to be connected with one pole of battery X, the other pole of which is to be connected to binding-post z ,.which is connected with one side of hingef, the other side of which is connected by wire 10 with springfinger I. The pin a at the center of the diaphragm touches the inner side of the rocking lever F at one side ofits pivot and at a point nearer to pin h than to pin 7:. The carbon electrode K is adjusted to bear normally but lightly on the inner end of pin 72, and said pin is always in contact with the spring-finger I. The circuit of the battery X is thus normally closed through the outer primary coil of the inductioncoil. At this time pin h is in contact Willi spring finger i and just out of contact with carbon electrode K. Now, if the .diaphragm makes an inward half-vibration,

it moves the rocking lever F to force the pin hinto contact with carbon electrode K and break the contact of pin it with carbon electrode K, thus breaking the circuit of the outer primary coil. As the spring-finger I follows pin it and never breaks contact therewith, the circuit is closed through the inner primary coil as soon as said pin touches thecarbon electrode K, which is immediately after the breaking of the contact between pin h and carbon K. Both the rlosing of one and the breaking of the other produce inductive effect upon the secondary, and the winding or direction of current in the two primaries is such that the breaking of one induces a current in the same direction as does the closing of the other, and their combined effect is to induce in the secondary very powerful impulses which fiow on the connected line and actuate with great force the receiving-instr u ments included therein. The outer half-vibration of the diaphragm of course restores the parts to their normal position, breaking one .circuit and closing the other. \Vhile it is true that there is an instant of time between the breaking of one primary circuit and making of the other, and vice versa, the making and breaking of said circuits are so rapid that every word and every part of every word spoken in front of the instrument is taken up and transmitted clearly and distinctly. This result is due to the peculiar construction of the instruments embodying the invention in each of the forms shown.

In the modified construction of the circuitclosing and breaking devices illustrated in Fig. 5 the carbon electrodes K K are supported in the same manner as shown in Fig. 1, the only difference being that they project inwardly from the door on opposite sides of the diaphragm. I11 this modification the rocking lever F has one insulated contact-pin, h", at only one end, while at the other end a pin, h", in metallic connection with the lever is arranged to make contact with the carbon electrode K. There is but one lower springfinger, as at I", and it is arranged to make contact with the forward end of pin h while .the rear end of said pin makes contact with the carbon electrode K. The pin 0 at the center of the diaphragm touches the rocking lever F on one side of its pivot nearest the pin h. The spring-finger I is constructed to press the pin 72, into normal contact with the carbon electrode K, and at such time the pin h, at the other end of the lever,

is just out of contact with the carbon electrode K. The outer terminal of the outer primary coil of the induction-coil M is connected by a wire, 10 ,with one pole of the battery X the other pole of which is connected by a wire, to, with the spring-finger I, and the inner terminal of this outer primary is connected by a wire, w,with the arm Z, supporting the stripspring 75, which carries the carbon electrode K. The outer terminal of the inner primary coil is connected bya wire, to, with one pole of the battery Xflwhich has its other pole connected by a wire, w",with the arm f, which supports and is in electric connection with the rocking lever F, and the inner terminal of said inner primary is, by a wire, w, connected with the spring-arm Z, supporting the strip-spring k, which carries the carbon electrode K. The secondary circuit of the induction coil is to be connected to line the same as in the firstdescribed instrument. The pin h in the normal condition of the instrument, is always in contact with spring-finger I", and the carbon electrode K is also in like contact with the inner end of pin If, and the pin it" is just out of contact with the carbon electrode K. Now, when the diaphragm D moves inwardly, the

pin 0 forces the lever F in such direction as to I put the pin its in contact with the carbon elec trode K, thus closing the circuit of battery X, and at the same time the pink is carried down out of contact with carbon electrode K, thus breaking the circuit of battery X The circuit being thus closed through one primary coil and broken through the other, the same inductive effect is produced upon the secondary, as in the first-described form of the apparatus.

In the modified form of the apparatus illustrated in the diagram Fig. 6, an arm, 0, projects inwardly from the center of the diaphragm D. An equal-armed lever, F is pivoted at one side to the inner end of this arm by means of a projectiomf and at its other side it is pivoted by a similar projection to the end of abent arm, F", projecting from the door oftheboX. From theoppositeendsofthisequalarmed lever pins 0 and 0* project downward, and are arranged to make contact alternately with carbon electrodes K and K", which are supported by springs s 8. (Shown in section.) The inner terminal of the outer primary-coil of the induction-coil M is connected by a wire, 10 to one pole of a battery, X, the other pole of which is connected by a wire, w", to pin k on arm of lever I, which is next to the diaphragm, and the outer terminal of said primary is connected by a wire, 10, with the carbon electrode K. The inner terminal of the inner primary is connected by a wire, w, with one pole of a battery, X which has its other pole connected by a wire, 10 with the pin h on arm of lever F, which is turned away from the diaphragm, and the outer terminal of this inner primary is connected by a wire, 10', with the carbon electrode K. This apparatus will be normally constructed so that the pin at the end of lever F next to the diaphragm will be lightly in contact with the carbon electrode K and the pin at the other end will be just out of contact with carbon electrode K. Now, when the diaphragm moves inwardly, the arm 0 will rock the lever I" so as to raise the pin at the end next to the diaphragm out of contact with carbon electrode K while throwing the pin at the other end in contact with elec trode K Thus the circuit will be alternately closed and broken through the respective primaries of the induction-coil with the same effect of double induction produced by the two forms of the apparatus previously described.

I make no claim herein to the method of transmitting speech, as that is claimed in my application filed January 14:, 1885, (Serial No. 152,864,) of which this application is a division.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a telephone-transmitter, the combina tion, with a diaphragm or vibrator and an induction-coil having two primary circuits which are on opposite sides of its secondary circuit, of circuit closing and breaking devices included in said primary circuits, respectivel y, and arranged to break one of said circuits and close the other in response to each half'vibration of the diaphragm, substantially as described.

2. In a telephonetransmitter, the combination, with a diaphragm and an induction-coil having two primary circuits, one on each side of its secondary circuit, of circuit closing and breaking devices included in each separate p imary circuit, the electrical currents of which flow from the same poles of two separate batteries through the electrodes and the primary wires of said induction-coil, the electrodes being operated by the vibrations of the diaphragm to produce a closing action of one set and a breaking action of the other set of said circuit closing and breaking devices, as set forth.

In a telephonic transmitter, the combina tion, with the diaphragm, and an inductioncoil having two primaries whichfare respectively on opposite sides of its secondary, of the rocking lever arranged to be rocked, and a pair of electrodes in the circuit of each of said primaries arranged to be controlled by the opposite ends of said rocking lever, respectively, one pair beinglbrought into electric connection by the movement of one end immediately after the other pair is electrically disconnected by the movement of the other end of said lever, substantially as described.

4. The combination, with the diaphragm, the rocking lever and the intermediate actuating-pin on one side of the pivot of the said lever, of the insulated contact-pins carried by said lever at its opposite ends, and the spring- I of said primaries, and arranged for operation 10 supported electrodes arranged to contact with by the diaphragm, substantially as described. the opposite ends of each of said pins, sub- In testimony whereof I affix my signature in stantially as described. presence of two witnesses.

5. In a tele )honic transmitter, the combina tion, with a diaphragm and an induction-coil l JALIES FREEDIAN' having two primaries, one on each side of a common secondary coil, of circuit closing and breaking devices included in circuit with each Vitnesses:

CHARLES S. HYER, J NO. B. SHIPMAN. 

